上篇说过添加水印的方案,帧数据转为Bitmap,在bitmap上画水印,然后将加了水印的Bitmap转为帧数据
这种方案可以实现水印添加,尽管用了RenderScript内联函数 增加了效率,但是因为多了帧数据到bitmap再到帧数据的转换过程,所以整体效率还是慢
针对此问题,为了提高效率,我们可以直接在获取到的YUV帧数据上直接添加水印的YUV数据,具体步骤:
1、提前将水印内容画在Bitmap上并将Bitmap转为YUV格式的字节数组
2、获取到视频原始帧数据
3、将水印的YUV数组里有效地水印部分对应赋值到原始帧数据相应位置
1、水印内容画到Bitmap再转为字节数组 这里bitmap是黑底白字,之所以黑底是方便我们后边合成YUV帧数据根据颜色做判断
private byte[] getOsdByte() { Bitmap bitmap=Bitmap.createBitmap(width,height, Bitmap.Config.ARGB_8888) Canvas canvas = new Canvas(bitmap); canvas.drawColor(getResource.getColor(R.color.black)); Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); paint.setColor(Color.WHITE); paint.setTextSize(80); canvas.drawText("毕哥制作", CameraSettings.SRC_IMAGE_WIDTH/2, 100, paint); byte[] newBytes = bitmapToNv12(bitmapAllNew,CameraSettings.SRC_IMAGE_WIDTH, CameraSettings.SRC_IMAGE_HEIGHT); if(newBytes!=null){ return newBytes; }else{ return null; } }
byte[] bitmapToNV12(int inputWidth, int inputHeight, Bitmap scaled) { int[] argb = new int[inputWidth * inputHeight]; scaled.getPixels(argb, 0, inputWidth, 0, 0, inputWidth, inputHeight); byte[] yuv = new byte[inputWidth * inputHeight * 3 / 2]; encodeYUV420SP(yuv, argb, inputWidth, inputHeight); scaled.recycle(); return yuv; } public static void encodeYUV420SP(byte[] yuv420sp, int[] argb, int width, int height) { final int frameSize = width * height; int yIndex = 0; int uvIndex = frameSize; int a, R, G, B, Y, U, V; int index = 0; for (int j = 0; j < height; j++) { for (int i = 0; i < width; i++) { a = (argb[index] & 0xff000000) >> 24; // a is not used obviously R = (argb[index] & 0xff0000) >> 16; G = (argb[index] & 0xff00) >> 8; B = (argb[index] & 0xff) >> 0; // well known RGB to YUV algorithm Y = ( ( 66 * R + 129 * G + 25 * B + 128) >> 8) + 16; U = ( ( -38 * R - 74 * G + 112 * B + 128) >> 8) + 128; V = ( ( 112 * R - 94 * G - 18 * B + 128) >> 8) + 128; // NV21 has a plane of Y and interleaved planes of VU each sampled by a factor of 2 // meaning for every 4 Y pixels there are 1 V and 1 U. Note the sampling is every other // pixel AND every other scanline. yuv420sp[yIndex++] = (byte) ((Y < 0) ? 0 : ((Y > 255) ? 255 : Y)); if (j % 2 == 0 && index % 2 == 0) { yuv420sp[uvIndex++] = (byte)((U<0) ? 0 : ((U > 255) ? 255 : U)); yuv420sp[uvIndex++] = (byte)((V<0) ? 0 : ((V > 255) ? 255 : V)); } index ++; } } }
2、获取到视频帧数据就不多说了 获取到的帧数据 该转颜色格式的转颜色格式 参考我之前的博客:https://www.cnblogs.com/bimingcong/p/14082860.html
3、将水印的YUV数组里有效地水印部分对应赋值到原始帧数据相应位置
//本方法是将NV12格式的水印数据的有效部分(即上边所说的黑底白字的白字部分)覆盖到原始NV12视频帧数据上
将数组B对应的值覆盖到数组A
offset_x是B在A的X轴偏移量
offset_y是B在A的Y轴偏移量
// public static void mergeOsd(byte[] nv12_A, byte[] nv12_B, int offset_x, int offset_y, int a_width, int a_height, int b_width, int b_height) { for (int i = 0; i < b_height; i++) { for (int j = 0; j < b_width; j++) { if(nv12_B[i * b_width + j] != 16){//如果不是黑色则将水印像素添加上去,黑色(#ff000000)就是黑底 值为16 nv12_A[i * a_width + offset_y * a_width + j + offset_x] = nv12_B[i * b_width + j]; } } } }
这样数组A就是覆盖完有效水印的帧数据了 可以放入编码器编码了